DAVID MARK: A University of Sydney report has found fewer students are studying maths and science for their HSC.

The report says Australia risks falling even further behind in international education benchmarks and so recommends the subjects should be compulsory.

Rachael Brown reports.

RACHAEL BROWN: University of Sydney researchers say the number of students choosing maths and sciences for their HSC is flagging.

RACHEL WILSON: Students used to have to choose at least one maths or science subject and they no longer have had to do that since 2001 and we have been able to document the decline that's been in response to that.

RACHAEL BROWN: Dr Rachel Wilson says the decline has been the steepest in maths.

And regarding study combinations; in 2011 only 16.2 per cent of students completed a maths/science combination for their HSC. This is 2 per cent less, than a decade ago.

RACHEL WILSON: There are really substantial issues at the university level where students are coming in without the adequate background in science and particularly maths skills for the degrees that they have chosen.

RACHAEL BROWN: Dr Wilson says there's no national database the researchers can mine. Nonetheless, she says the figures paint a depressing picture about Australia's international competitiveness.

RACHEL WILSON: Look, it's very clear that countries like South Korea have made very rapid progress. Japan's been a consistently high performer in science and maths. Russia as well has recently joined the international studies and is performing very, very well.

RACHAEL BROWN: Is there are danger that if you force students to study maths and sciences who aren't able or aren't equipped to deal with such subjects that that could bring their score right down?

RACHEL WILSON: There are issues there, but what I would say is that we perhaps need to have a broader conversation about what it is that we think secondary high school education should be about.

I can't find another developed country which doesn't require maths for high school graduation.

We're now at the situation where students have such control and choice over the subjects that they choose, I think it is sort of threatening core educational curriculum and we can see, for example, the move away from maths has left us in a situation where we may run into real skills shortages and create problems for our future economy unless we do something about it.

RACHAEL BROWN: Across the border, Victoria's Curriculum and Assessment Authority says it has no plans to make the subjects compulsory at VCE level.

It says last year, maths and science studies represented half of the top 10 most popular subjects.

However the authority says it's offering scholarships to support science graduates to become science teachers and it's training 200 primary school teachers to become maths and science specialists.

The Australian Education Union's Correna Haythorpe says this grass roots investment is crucial.

CORRENA HAYTHORPE: Well we want our students to be engaged with respect to maths and science and certainly when they have vibrant teacher role models who are teaching in those fields then there is, I think, a good level of interest from students taking up those programs.

DAVID MARK: The Australian Education Union's Corenna Haythorpe. Rachael Brown was our reporter.